Such interface modules are used in different applications. One possibility is, for example, to replace a memory module of a control unit with such an interface module having an integrated component. The actual memory module, for example, an EPROM, EEPROM, flash memory, RAM, etc., is replaced by an interface module having an emulator memory, e.g., via an emulator probe. Such an interface module may also be referred to as a memory interface. This memory interface makes it possible to access memory data of a control unit using a software tool via an external device known as a tool computer (e.g., a PC) and execute measuring and calibration applications on the control unit.
However, microcontrollers of a control unit itself may also be replaced by this interface module having an integrated component, in which case the component is a microcontroller. For this reason, the interface module having an integrated component is referred to hereinafter as a microcontroller interface. This designation, however, should not be regarded as a limitation with respect to the application, as evidenced by the above discussion.
Microcontroller interfaces are in particular devices enabling a software tool to access signals of microcontroller units (MCU). The microcontroller is installed at the site of use (e.g., in a control unit in the engine compartment of a motor vehicle) and is situated on a control unit board or circuit board. The software tool is executed on an external computer, known as a tool computer (for example, a PC). Using this design, different activities may be performed.                Measurement & Calibration        Rapid-Prototyping        Debugging and/or Error Tracing        
The related art is the use of a printed circuit which is installed between the control unit board and the microcontroller. For this purpose, the microcontroller is removed from the standard control unit and replaced by an intermediate base. The microcontroller interface, which contains the electronic components needed for protocol conversion, access for the software tool, i.e., the tool computer (plug or cable), and a microcontroller in a standard housing, is plugged onto this intermediate base. This design and the additional electronic components make the surface area of the microcontroller interface, i.e., the interface module, considerably larger than the surface area of the microcontroller itself.
This represents a disadvantage, since no high components should be situated on the control unit board under the interface module, i.e., the microcontroller interface. Furthermore, it must be made sure that the interface module does not protrude over one or more sides beyond the circuit board surface of the control unit. Tool manufacturers and control unit manufacturers must precisely coordinate the mechanical dimensions of their particular products. This is difficult, since in particular in the starting phase of control unit development, the arrangement of the components may change considerably. Nevertheless, the interface module or interface development must be started as early as possible, since the microcontroller interface must be available at the same time as the control unit.
The monolithic design represents another disadvantage. The entire interface module having the integrated component, adapted to the installation site and having the signals adapted for transmission onto the tool computer, is implemented inseparably in a printed circuit. The adaptation to the installation site is, however, dependent on the mechanical shape (e.g., housing) and on the type of the microcontroller, while adaptation of the signals depends on the activity performed. For example, when measuring and adjusting, microcontroller functions and interfaces other than in debugging must be accessed. Therefore, a large number of interface module or interface variants results, which are complicated to manufacture and to manage.
It is apparent that the related art has not succeeded in delivering optimum results in all respects. Therefore, an object of the present invention is to provide an interface module which has a high degree of flexibility regarding the installation site, while the number of variants may be limited.